When Amazon announced its new streaming music service, it butted its way in to a room already crowded with players. Some, like Pandora, focus on custom radio-like experience, while others, such as Beats and Spotify, offer vast catalogs of music on-demand for a flat monthly fee. Apple and Google (and now, too, Amazon) stream music in various ways, in order to appeal to widely differing preferences of their users.

Here’s a quick guide to all the streaming music options that matter:

Pandora

How many songs? 1.5 millionWhat’s the cost? Free ad-supported streaming, $3.99 per month for premium ad-free service

Pandora’s success has been based on its simplicity and wide availability, not to mention its main free option. You pick an artist and it creates a “station” based on similar artists, and you can create up to 100 personalized stations with your free account.

You can get it for Android, iOS, Kindle Fire, Nook, Windows Phone, BlackBerry and the Web (not to mention in cars and on smart TVs). The downsides are that there’s no on-demand all-you-can-eat option, nor is there offline listening.

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Apple iTunes Music with iTunes Radio

How many songs? 40 million in store; Apple doesn’t specify number of tracks in iTunes RadioWhat’s the cost? Apple charges a la carte for music, but also has $24.99/year iTunes Match streaming; iTunes Radio is free

A few years ago, Apple’s download store added iTunes Match, a $24.99 per year service that lets you stream music you own (not just store purchases) to all of your authorized iOS devices. Then, Apple introduced iTunes Radio, a free streaming radio service that lets you customize your own stations a la Pandora. It’s supported by ads, unless you have the Match subscription.

There’s no option for Android or any other non-Apple platform—besides Windows PCs running iTunes—and there isn’t a Web-based music player either. While those are currently the only streaming offerings from Apple, the company did recently announce its intent to buy Beats Audio. Plans for the Beats Music service will likely be revealed soon.

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Spotify

How many songs? “Millions,” says SpotifyWhat’s the cost? $9.99 for unlimited streaming and on-demand music; free ad-supported options for Web and mobile

The current top dog in the subscription on-demand space, Spotify lets you stream music or download it for offline listening. You can subscribe to playlists created by other users, or share what you’re listening to in realtime on Facebook.

The free version lets you listen to artists, albums or playlists on demand, but the tracks play in shuffled order, and are interspersed with ads.

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Google Play Music

How many songs? 22 millionWhat’s the cost?All Access pass is $9.99 per month; Google also sells tracks and albums individually

With the All Access pass, you get on-demand streaming and downloading of millions of songs, plus the ability to manually add up to 20,000 of your own songs, even sync your iTunes library. The services is available for Android, iOS and the Web.

There’s also a custom radio service similar to Pandora.

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Amazon Music with Prime

How many songs? 20 million in MP3 store, “over a million” available for Prime subscription serviceWhat’s the cost? Included with Amazon Prime $99/year subscription

All of your Amazon music purchases and Amazon cloud drive uploads appear in your library. Prime subscribers can add to this from a catalog of around 12,000 albums, and a whole bunch of playlists. From there, you can stream or download to your device. Amazon Music is on iPhone, iPad, Android devices and of course, the Kindle Fire tablets.

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Beats Music

How many songs? 20 millionWhat’s the cost? $9.99 per month or $99.99 per year; no free option

Beats Music merges the best of Spotify, Pandora and Rdio with a fresh approach to song recommendation. Yes, for $9.99 per month you can download the songs you want, but you can also participate in exercises like “The Sentence,” which lets you Mad Lib your way to new artists. Already available for iOS, Android, Windows Phone and on Web browsers, Beats Music was a main driver behind Apple’s $3 billion acquisition of the Beats Music and Beats Electronics.

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Rdio

How many songs? “Over 20 million tracks,” says RdioWhat’s the cost? $9.99 per month for main plan, but other options include $4.99 student plan and discounts for families; free ad-supported options for mobile and Web

Not as popular as Spotify but a favorite for many, Rdio is available on iOS, Android and Windows Phone, as well as on Macs using a desktop app. There’s also free streaming on the Web (with ads), and a free mobile option that lets you listen to preset stations. People like Rdio’s social integration, too.

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The Others

There are other music services worth mentioning here, chief among them YouTube. Yes, YouTube. Google’s free video service happens to be one of the main places where people catch new music, and you can pretty much find any song you want when you search. The downsides are many: No albums, no offline mode—heck, you can’t even turn the screen off on your device to just listen because the video will stop playing. But YouTube remains a key player.

Coming from the video-game quadrant of the galaxy, there’s Microsoft 's Xbox Music and Sony Music Unlimited; each are $9.99-per-month all-you-can-eat streaming services with millions of songs. Microsoft gives users a free taste through Windows 8 and on the Web; Sony offers discounted 6-month and 12-month pricing through GameStop.

Slacker Radio competes with Pandora, Spotify and Rdio with a 10-million song catalog and three program tiers: free, $3.99 Slacker Radio Plus, and a full premium unlimited on-demand subscription for $9.99. Samsung’s Milk Music, a free service for owners of the company’s Galaxy devices, leverages Slacker, but is free of ads for the time being.

Clear Channel’s free IHeartMusic also merits a nod. Though mainly geared for keeping up with real-life radio stations—over 1,500 from around the country—it also has a catalog of 18 million songs that are used to stream you custom stations based on your preferences.

Update: Due to popular demand, we’re going to mention two more: Songza, a quirky Pandora competitor that takes you through all kinds of fun scenarios to figure out exactly what song you’re in the mood for (available in both free and $3.99-per-month premium streams); and Rhapsody/Napster, the grandfather of the streaming Web music scene, whose $9.99-per-month service gives access to a global catalog of 32 million songs.